U.S. patent application number 11/200959 was filed with the patent office on 2006-02-16 for method and apparatus for wireless communication network operating in compressed mode.
This patent application is currently assigned to NEC Corporation. Invention is credited to Phong Nguyen.
Application Number | 20060034245 11/200959 |
Document ID | / |
Family ID | 35799855 |
Filed Date | 2006-02-16 |
United States Patent
Application |
20060034245 |
Kind Code |
A1 |
Nguyen; Phong |
February 16, 2006 |
Method and apparatus for wireless communication network operating
in compressed mode
Abstract
There is provided a method for use by a user equipment of a
Universal Mobile Telecommunication System (UMTS) that supports
HSDPA, and a network node in communication with such a user
equipment. In an embodiment the method includes, identifying a
transmission gap in a downlink transmission from a base station on
a first channel. Next the transmission gap is mapped onto a first
channel to define a first suspension period encompassing the
subframes of the first channel that overlap the transmission gap.
The method further includes expanding the first suspension period
to define a further period encompassing the subframes of at least
one further channel that overlap the first suspension period, and
defining a reception suspension period encompassing the further
period, and subframes associated with the subframes falling within
the further period.
Inventors: |
Nguyen; Phong; (Victoria,
AU) |
Correspondence
Address: |
DICKSTEIN SHAPIRO MORIN & OSHINSKY LLP
1177 AVENUE OF THE AMERICAS (6TH AVENUE)
41 ST FL.
NEW YORK
NY
10036-2714
US
|
Assignee: |
NEC Corporation
|
Family ID: |
35799855 |
Appl. No.: |
11/200959 |
Filed: |
August 10, 2005 |
Current U.S.
Class: |
370/345 |
Current CPC
Class: |
H04W 76/28 20180201;
Y02D 30/70 20200801 |
Class at
Publication: |
370/345 |
International
Class: |
H04J 3/00 20060101
H04J003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 2004 |
AU |
2004904512 |
Claims
1. A method of operating a user equipment in compressed mode during
high speed downlink packet access activity, the method comprising;
identifying a transmission gap in a downlink transmission from a
base station; identifying one or more data subframes that overlap
the transmission gap; determining a reception suspension period
encompassing the identified subframes and the transmission gap; and
suspending high speed data packet reception by the user equipment
during the reception suspension period.
2. A method as claimed in claim 1 wherein the method further
comprises, suspending processing of high speed downlink packet
access packets during the reception suspension period.
3. A method as claimed in claim 1 wherein the reception suspension
period also encompasses data subframes that are associated with the
identified data subframes.
4. A method as claimed in claim 1 wherein the reception suspension
period encompasses one or more data subframes having associated
data subframes that overlap the transmission gap.
5. A method as claimed in claim 1 wherein the reception suspension
period encompasses data subframes identified as belonging to an
extended transmission gap on the basis of higher network layer
parameters.
6. A method of determining a reception suspension period for a user
equipment in compressed mode during high speed downlink packet
access activity, the method comprising: identifying a transmission
gap in a downlink transmission from a base station; mapping the
transmission gap onto a first channel to thereby define a first
suspension period encompassing the subframes of the first channel
that overlap the transmission gap; expanding the first suspension
period to thereby define a further period that encompasses the
subframes of at least one further channel that overlap the first
suspension period; and defining a reception suspension period
encompassing the further period, and subframes associated with the
subframes falling within the further period.
7. A method as claimed in claim 6 wherein the first channel
comprises a common pilot channel.
8. A method as claimed in claim 6 wherein the at least one further
channel comprises a high speed downlink shared channel and/or a
high speed shared control channel.
9. A method as claimed in claim 6 wherein the step of defining the
reception suspension period comprises defining the reception
suspension period to additionally encompass one or more data
subframes specified on the basis of higher network layer
parameters.
10. A method for controlling a base station of a cellular
telecommunications network communicating with user equipment in
compressed mode during high speed downlink packet access activity,
the method comprising: determining a reception suspension period
using a method according to claim 6; and suspending transmission of
high speed downlink packet access packets to the user equipment
during the determined reception suspension period.
11. A method of managing power consumption in a user equipment, for
a cellular telecommunications network, operating in compressed mode
during high speed downlink packet access activity, comprising:
determining a reception suspension period using a method according
to claim 6; and suspending reception and/or processing of high
speed downlink packet access packets during the reception
suspension period.
12. A user equipment for a Mobile Telecommunication System network
configured to be operated in compressed mode during high speed
downlink packet access activity, the user equipment comprising: a
section to identify a transmission gap in a downlink transmission
from a base station of the network; a section for identifying one
or more data subframes that overlap the transmission gap; and a
section for determining a reception suspension period encompassing
the identified subframes and the transmission gap; and wherein the
user equipment is configured to suspend high speed data packet
reception during the reception suspension period.
13. A user equipment as claimed in claim 12, further configured to
suspend processing of HSDPA packets during the reception suspension
period.
14. A base station of a cellular telecommunications network for
communicating with user equipment in compressed mode during high
speed downlink packet access activity, the base station comprising:
a section for determining a reception suspension period for the
user equipment in accordance with the method according to claim 6;
and a scheduling section for scheduling transmission of high speed
downlink packet access packets to the user equipment, and wherein
the scheduling section does not schedule high speed downlink packet
access packets for transmission to the user equipment during the
determined reception suspension period.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and an apparatus
for wireless communication network, preferably Universal Mobile
Telecommunication System (UMTS), operating in compressed mode, and
in particular, to the method and the apparatus for use by a user
equipment that supports HSDPA, and a network node in communication
with such a user equipment.
[0003] 2. Description of the Related Art
[0004] High Speed Downlink Packet Access (HSDPA) is emerging as a
promising candidate for providing high bit rate transmission of
packetized data in third generation wireless telecommunication
networks. It is expected that once implemented Wideband Code
Division Multiple Access (WCDMA) networks using HSDPA will be able
to provide data transmission at rates in the order of 10 Mbps.
[0005] In the HSDPA method, as a physical channel for a downlink
through which data are transmitted from a base station to a mobile
wireless terminal, an HS-SCCH (High Speed-Shared Control CHannel)
and an HS-PDSCH (High Speed-Physical Downlink Shared CHannel) are
additionally provided. The HS-SCCH is used to transmit control
information of the HS-PDSCH pairing up with the HS-SCCH, while the
HS-PDSCH is used to transmit packet data employed in the HSDPA
method. Moreover, the HS-PDSCH can use a maximum 15 pieces of
channelization codes in units of subframes, which is called a
multi-code, and the number of used multicodes is called the
multicode number. The subframe denotes a frame length of a physical
channel used in the HSDPA method expressed in time units of three
slots and a slot denotes a time unit designated by the 3GPP.
[0006] The implementation of HSDPA specified by the 3rd Generation
Partnership Project (3GPP) requires that any transmission scheme
used for HSDPA is compliant with the compressed mode used by UMTS
user equipments when performing inter-frequency or inter-system
measurement as a preparation for a handover.
[0007] As will be known to those skilled in the art a handover is a
process whereby the user equipment changes the way in which it
access the radio network, for example, by changing cell or radio
access mode.
[0008] In a UMTS network if a user equipment is required to perform
a inter-frequency or inter-system handover, the node B (base
station) instructs the user equipment to operate in the compressed
mode. In compressed mode a gap is created by obeying predefined
patterns in certain radio frames transmitted between the node B and
user equipment, in which the node B and user equipment can perform
various measurements of network parameters to prepare for the
handover. For example, base stations in cells surrounding the
current cell of user equipment may perform signal strength
measurements for the user equipment in order to determine which of
the base stations the user equipment should handoff to. In the
downlink direction a transmission gap is inserted into
predetermined frames on the Dedicated physical channel (DPCH).
[0009] One of the drawbacks of HSDPA is that the high data
reception rate at the user equipment requires a large amount of
digital signal processing to be performed in the user equipment and
this processing burden has a detrimental effect on the battery life
of user equipments.
SUMMARY OF THE INVENTION
[0010] In view of the above, it is an object of the present
invention to provide a method and an apparatus for a wireless
communication network operating in compressed mode being capable of
overcoming one or more disadvantages of the prior art, for example,
capable of saving unnecessary processing power and hence enhancing
battery life.
[0011] In a first aspect the present invention provides a method of
operating a user equipment in compressed mode during high speed
downlink packet access (HSDPA) activity, the method including;
[0012] identifying a transmission gap in a downlink transmission
from a base station;
[0013] identifying one or more data subframes that overlap the
transmission gap;
[0014] determining an reception suspension period encompassing the
identified subframes and the transmission gap; and
[0015] suspending high speed data packet reception by the user
equipment during the reception suspension period.
[0016] The method can also include suspending processing of HSDPA
packets during the reception suspension period.
[0017] Preferably the reception suspension period also encompasses
data subframes that are associated with the identified data
subframes. The reception suspension period may also encompass one
or more data subframes having associated data subframes that
overlap the transmission gap.
[0018] In further embodiments the reception suspension period also
encompasses data subframes identified as belonging to the extended
transmission gap on the basis of higher network layer
parameters.
[0019] In the present application a data subframe should be
understood as being associated with another data subframe if they
form part of the same frame. For example, a high speed shared
control channel (HS-SCCH) subframe will have an associated high
speed downlink shared channel (HS-DSCH) subframe.
[0020] In a further aspect the present invention provides a method
of determining a reception suspension period for a user equipment
in compressed mode during high speed downlink packet access (HSDPA)
activity, the method including:
[0021] identifying a transmission gap in a downlink transmission
from a base station on a first channel;
[0022] mapping the transmission gap onto a first channel to thereby
define a first suspension period encompassing the subframes of the
first channel that overlap the transmission gap;
[0023] expanding the first period to thereby define a further
period that encompasses the subframes of at least one further
channel that overlap the first suspension period;
[0024] defining a reception suspension period encompassing the
further period, and subframes associated with the subframes falling
within the further period.
[0025] Preferably the first channel is a common pilot channel.
[0026] The at least one further channel can be selected from a
group including, a high speed downlink shared channel and a high
speed shared control channel.
[0027] The step of defining the reception suspension period can
include defining the reception suspension period to additionally
encompass one or more data subframes specified on the basis of
higher network layer parameters.
[0028] In a third aspect there is provided a method for controlling
a base station of a cellular telecommunications network
communicating with user equipment in compressed mode during high
speed downlink packet access (HSDPA) activity, the method
including:
[0029] Determining a reception suspension period in accordance with
any of the above methods; and
[0030] suspending transmission of HSDPA packets to the user
equipment during the determined reception suspension period.
[0031] In a further aspect the present invention provides a method
of managing power consumption in a user equipment in compressed
mode during high speed downlink packet access (HSDPA) activity,
including:
[0032] determining a reception suspension period in accordance with
any of the above methods; and
[0033] suspending reception and/or processing of HSDPA packets
during the reception suspension period.
[0034] In a further aspect the present invention provides a user
equipment for a Universal Mobile Telecommunication System (UMTS)
network configured to be operated in compressed mode during high
speed downlink packet access (HSDPA) activity, the user equipment
including, a section to identify a transmission gap in a downlink
transmission from a base station of the network; a section for
identifying one or more data subframes that overlap the
transmission gap; a section for determining a reception suspension
period encompassing the identified subframes and the transmission
gap; wherein the user equipment is configured to suspend high speed
data packet reception during the reception suspension period.
[0035] Preferably the user equipment is further configured to
suspend processing of HSDPA packets during the reception suspension
period.
[0036] The user equipment is preferably configured to determine a
reception suspension period using any one of the methods described
herein.
[0037] In another aspect the present invention provides a base
station of a cellular telecommunications network for communicating
with user equipment in compressed mode during high speed downlink
packet access (HSDPA) activity, the base station including, a
section for determining a reception suspension period for the user
equipment in accordance with the method of any one of claims 6 to
9; and a scheduling section for scheduling transmission of HSDPA
packets to the user equipment, wherein the scheduling section does
not schedule HSDPA packets for transmission to the user equipment
during the determined reception suspension period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The above and other objects, advantages, and features of the
present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings in
which:
[0039] FIG. 1 depicts a schematic representation of a system
sending a HSDPA service operating in compressed mode in accordance
with an embodiment of the present invention;
[0040] FIG. 2 is a block diagram of a HSDPA packet scheduling and
transmission processing arrangement of a base station operating in
accordance with an embodiment of the present invention;
[0041] FIG. 3 is a schematic block diagram of the layer 1 processes
taking place in a user equipment according to an embodiment of the
present invention;
[0042] FIG. 4 shows a flowchart showing the steps in a method of
defining a reception suspension period in an embodiment of the
present invention;
[0043] FIG. 5 shows a diagram illustrating the mapping of a
transmission gap on the DPCH onto other channels in a WCDMA network
using in an embodiment of the present invention;
[0044] FIG. 6 shows a diagram illustrating a more detailed view of
the mapping of the transmission gap on the DPCH onto other channels
in a WCDMA network using in an embodiment of the present invention;
and
[0045] FIG. 7 shows a diagram illustrating how data subframes
specified on the basis of higher network layer parameters can be
used to define an extended reception suspension period in an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] Best modes of carrying out the present invention will be
described in further detail using various embodiments with
reference to the accompanying drawings.
[0047] According to 3GPP Rel'5 specification 25.214 when a WCDMA
user equipment is operating in compressed mode the user equipment
shall neglect a high speed physical channel shared control channel
(HS-SCCH) or high speed physical downlink shared channel (HS-PDSCH)
transmission if a part of the HS-SCCH subframe or a part of its
associated HS-PDSCH subframe overlaps with a downlink transmission
gap on the associated DPCH.
[0048] In this regard the inventor has identified that the
reception and/or decoding of HSDPA data can be suspended during an
extended period (herein referred to as a reception suspension
period (RSP)) that includes at least the time period in which these
"neglected" subframes would be received. In certain embodiments the
suspension of the HSDPA activity in RSP may advantageously serve to
decrease the impact on battery resources of a user equipment when
conducting HSDPA activities in compressed mode.
[0049] FIG. 1 depicts a schematic diagram of a base station 10 in
communication with four user equipments 12, 14, 16, 18 that are
each receiving an HSDPA service. The user equipments 12 to 18 share
the HSDPA channel resources of the base station 10 by either code
division multiplexing or time division multiplexing or a
combination of both. The method of multiplexing is determined by an
HSDPA packet scheduler of the base station 10.
[0050] In the present example, the user equipment 18 has been
scheduled to operate in compressed mode. As described above, while
a user equipment 18 is operating in compressed mode, there exists a
transmission gap in which HSDPA packets are not sent to the user
equipment, and where certain received packets can be "neglected" by
the user equipment.
[0051] FIG. 2 shows a more detailed schematic block diagram of part
of the base station 10 of FIG. 1. In particular, FIG. 2 depicts a
block diagram of the MAC-hs protocol layer of the base station 10,
in which scheduling of HSDPA transmission is performed in the base
station.
[0052] The arrangement of the HSDPA packet scheduling and
transmission processing portion of the base station is similar to a
conventional base station capable of transmitting HSDPA services,
with the exception of the operation of the HSDPA packet scheduler
20 and Adaptive Modulation and Coding (AMC) controller 22. In
accordance with the methods described below, the HSDPA packet
scheduler 20 controls the use of the resources available for HSDPA
in each transmission time interval to perform packet transmission
scheduling so that the channel capability reserved for HSDPA
service is optimised.
[0053] In this regard, the HSDPA packet scheduler 20 also
calculates the extent of the transmission gap for any user
equipment (e.g. UE 18) that is operating in compressed mode and
schedules HSDPA packets so as to enforce the packet transmission
suspension for that user equipment during the calculated extended
transmission gap.
[0054] During the period extended transmission gap the HSDPA packet
scheduler 20 is able to schedule HDSPA packets for transmission to
other user equipments to improve the HSDPA system throughput.
[0055] The AMC controller performs the packet processing, including
changing channel coding, changing retransmission version, changing
channel modulation scheme for any user equipment according to
channel quality and packet acknowledgment reported from a user
equipment. For a given user equipment, the AMC controller 22
receives Channel Quality Indicator (CQI), and ACK/NACK information
and uses this data to calculate parameters for the retransmission
of old packets or transmission of a new packets. The extended
transmission gap data information for a particular UE is passed to
the AMC controller 22 from The HSDPA packet scheduler 20 to enable
the processing of packet transmission/retransmission.
[0056] According to an embodiment of the present invention the
HSDPA packet scheduler 20 does not schedule any new or
retransmitted packet to a UE operating in compressed mode during
the calculated extended transmission gap. As will be apparent from
the following discussion the HSDPA packet scheduler 20 can utilise
the radio resources freed-up by this process for transmitting HSDPA
packet to other user equipment within the cell.
[0057] The HSDPA data packets for each UE (e,g, UEs 12 to 18 of
FIG. 1), as scheduled by the HSDPA packet scheduler 20, are then
further processed by convention processing blocks 24, before
multiplexing in block 26 and physical channel processing in block
28 per current 3GPP Rel'5 and Rel'6 HSDPA requirements.
[0058] FIG. 3, which shows a schematic view of the relevant layer 1
components of a user equipment (e.g. UE 18) configured to be used
in implementations of the present invention. In this regard the
user equipment (e.g. UE 12 of FIG. 1) receives a radio frequency
signal 30. The HSDPA demodulator 42 demodulates the HSDPA data
received on the digital base band. Control channel data is passed
to the HSDPA Layer 1 controller 44 to enable control of the
decoding of the received HSDPA data by the HSDPA control decoder
46. HSDPA data is passed to the HSDPA data decoder 48. As will be
appreciated from the following description of embodiments of the
present invention, when the UE 40 is operating in compressed mode
the HSDPA Layer 1 controller 44 is adapted to compute a reception
suspension period, in the manner described below, during which the
operation of the HSDPA demodulation stage and other blocks can
serve to save power.
[0059] In practice, the reception suspension period (RSP) can be
determined for a user equipment operating in compressed mode during
HSDPA activity according to the method depicted in FIG. 4. The
method 100 begins 102 when the user equipment is directed by the
node B to enter compressed mode. In compressed mode transmissions
in the downlink physical channel (DPCH) will include a transmission
gap (TG), having a set transmission gap length (TGL) in certain
data frames.
[0060] The method begins (step 102) by identifying a transmission
gap in the DPCH transmission from a base station. Next (step 104)
the transmission gap is mapped onto the common pilot channel
(CPICH) to determine a first period. The first period is determined
by ascertaining which slots on the CPICH will overlap the TG, and
defining the first period, as beginning at the start of the CPICH
slot that overlaps the beginning of the TG, and ending at the end
of the CPICH slot that overlaps the end of the TG.
[0061] Next, in step 106, the first period is expanded to define a
second period that encompasses high speed physical channel shared
control channel (HS-SCCH) subframes and/or high speed physical
downlink shared channel (HS-PDSCH) subframes which overlap the
first period. The second period begins at the start of the HS-SCCH
or HS-PDSCH subframe that overlaps the beginning of the first
period, and ends at the end of the HS-SCCH or HS-PDSCH subframe
that overlaps the end of the first period.
[0062] Finally, in step 108 the RSP can be determined. In general
the RSP will be defined as beginning a the earliest of; the
beginning of the TG; the beginning of the first period; and the
beginning of the second period or the start of a subframe
associated with a subframe falling within the second period; and
will end at the latest of; the end of the TG; the end of the first
period; and the end of the second period.
[0063] The process can be further explained with reference to FIG.
5 illustrating relative timing of transmissions on the CPICH,
HS-SCCH and DPCH. In accordance with the method described above in
connection with FIG. 4, the transmission gap 202 in the DPCH
transmission 200 is mapped 204 onto the CPICH 206 (Step 104). The
mapping is used to determine those slots 208, 210 on the CPICH that
will overlap the transmission gap 202.
[0064] The first period 212 can then be defined, which begins at
the start of CPICH slot 210 which overlaps the beginning of the TG
202 and ending at the end of CPICH slot 208 that overlaps the end
of the TG 202.
[0065] This first period 212 can then be expanded 214 to define a
second period 220 that encompasses any frames of the high speed
physical channel shared control channel (HS-SCCH) 216, or high
speed physical downlink shared channel (HS-PDSCH) 218 that overlap
the first period 212.
[0066] Finally, the RSP 222 can be determined. In general the RSP
222 will be defined as beginning a the earliest of; the beginning
of the TG 202 ; the beginning of the first period 212; and the
beginning of the second period 220; or the beginning of a subframe
224 associated with a subframe falling within the second period
220, and will end at the latest of; the end of the TG 202; the end
of the first period 212; and the end of the second period 220.
Thus, although HS-SCCH subframe 224 does not overlap the first
period 212 it is deemed to lie within the RSP 222 as its HS-PDSCH
subframe 218 overlaps the first period 212.
[0067] FIG. 6 depicts the relationship between the timing of
transmissions on the CPICH, HS-SCCH and DPCH and the TG, and the
corresponding first period, second period and reception suppression
period (RSP) in greater detail, and will be used to describe how
the RSP can be calculated by a user terminal. Where possible
reference numerals corresponding those used in FIG. 5 will be used
in the description of FIG. 6.
[0068] A determination as to when reception can be suspended, that
is, when the RSP begins and the duration of the RSP can be made as
follows.
[0069] Initially a determination is made as to which CPICH slot
numbers TGSN.sub.CPICH (210) overlap with the start of the
transmission gap 202. This can be done by applying the following
formula. TGSN CPICH = .tau. DPCH 10 + TGSN DPCH ##EQU1##
[0070] Where .tau..sub.DPCH is the DPCH from offset given by a
higher layer; and
[0071] TGSN.sub.DPCH is the DPCH slot number at the start of the
transmission gap 202.
[0072] The length of the first period 220 and hence the CPICH slot
overlapping the end of the TG202 can be determined as follows:
[0073] If .tau..sub.DPCH mod 10=0 then
TGL.sub.CPICH=TGL.sub.DPCH;
[0074] else TGL.sub.CPICH=TGL.sub.DPCH+1.
[0075] In FIG. 6 the length of first period is shown as
TGL.sub.CPICH 220.
[0076] Next the HS-SCCH subframes that overlap the first period 220
and consequently one mode are affected by compressed transmission
gap are identified as follows.
[0077] The HS-SCCH Subframe number of the HS-SCCH subframe at the
start of the second period indicated on FIG. 6 as TGSFN.sub.HS-SCCH
or 218 is determined using the following formulae:
[0078] If TGSN.sub.CPICH=2,5,8, 11 or 14 then TGSFN HS - SCCH =
TGSN CPICH 3 ##EQU2## otherwise TGSFN HS - SCCH = TGSN CPICH 3 - 1
.times. .times. and ##EQU3##
[0079] If TGSFN.sub.HS-SCCH<0, then TGSFN.sub.HS-SCCH=4 of the
previous CPICH frame.
[0080] The number of the HS-SCCH Subframe including the end of the
second period, indicated by TGEFN.sub.HS-SCCH in FIG. 6 can be
determined using the following formula: TGEFN HS - SCCH = ( TGSN
CPICH + TGL CPICH ) .times. .times. mod .times. .times. 14 3
##EQU4##
[0081] If (TGSN.sub.CPICH+TGL.sub.CPICH)>14 then the
TGEFN.sub.HS-SCCH ends in the CPICH frame which is ( TGSN CPICH +
TGL CPICH ) 14 ##EQU5## frames away from the CPICH frame which
contains the start of the first period TGSN.sub.CPICH 210.
[0082] All HS-SCCH subframes within the second period, that is, all
HS-SCCH subframes between TGSFN.sub.HS-SCCH and TGEFN.sub.HS-SCCH
are considered to fall within the RSP, and accordingly thus in the
present embodiment the RSP shall be the period from the
TGSFN.sub.HS-SCCH and TGEFN.sub.HS-SCCH.
[0083] As will be appreciated the transmission gap can be
identified in advance of the user equipment changing into
compressed mode, e.g. upon receipt of control data from a node B
directing it to do so. This allows the user equipment to suspend
the reception and processing of packets on the HS-SCCH channel and
its associated HS-PDSCH for the identified RSP to save unnecessary
processing power and hence to enhance battery life.
[0084] In a further exemplary embodiment of the present invention
the RSP can be extended to take account of control information from
higher layers. For example when a user equipment is undergoing
HSDPA activity in accordance with 3GPP specification TS 25.214, the
user equipment supporting HSDPA is mandated not to receive nor
decode transport blocks from the HS-PDSCH in the HS-DSCH (High
Speed-Downlink Shared Channel; transport channel) sub-frames n+1 to
n+(N_acknack_transmit-1). Where the N_acknack_transmit parameter is
given from higher layer signalling. As depicted in FIG. 7 the RSP
can be extended to include this additional group of subframes.
[0085] FIG. 7 shows the relationship between the timing of
transmissions on the CPICH, HS-SCCH and DPCH and the TG, and the
corresponding derived reception suppression period (RSP) of FIG. 5.
It also shows the HS-SCCH and the HS-DSCH sub-frames n+1 to
n+(N_acknack_transmit-1) mandated as non reception subframes by a
higher layer.
[0086] As can be seen in FIG. 7 the RSP 222 is initially defined in
the same manner described in relation to FIG. 5. However as
described above when an apparatus supporting HSDPA has detected
control information intended for it in the HS-SCCH sub-frame (n+1)
the apparatus can stop receiving/decoding data after the associated
HS-DSCH sub-frame (n+1). Knowing N_acknack_transmit it is possible
to calculate in advance the next HS-SCCH subframe, that is subframe
HS-SCCH (o+1) (indicated by reference numeral 224 in FIG. 7) at
which the monitoring of HS-SCCH should resume. However as shown in
FIG. 7 if the subframe HS-SCCH (o+1) 224 resides within the RSP 222
the user equipment supporting HSDPA shall be able to extend the RSP
222.
[0087] An extended RSP 504 can be defined to extend from the first
ignored HS-SCCH subframe 500, that is, subframe (n+2) to the end of
the initial RSP. This shall give effective RSP 504 in which all
HSDPA activities, with the exception of completing decoding data
packet from the HS-DSCH subframe (n+1), can serve to save
processing power.
[0088] In accordance with a further aspect of the present invention
a base station in communication with a user equipment can
temporarily suspend transmission to the user equipment during the
reception suspension period. In this regard, the node B has access
to all relevant data to enable it to calculate the RSP using the
same method as used by the user equipment. Thus the base station
can suspend transmission of data packets which will not be received
by the user equipment.
[0089] As will be appreciated by those skilled in the art by
suspending transmission from the base station to the user equipment
during the RSP calculated by the user equipment the resources of
the base station are conserved and are able to be applied to other
activities. As will be appreciated this may lead to a more
efficient usage of the network resources such as code sharing and
transmit power.
[0090] It will be understood that the invention disclosed and
defined in this specification extends to all alternative
combinations of two or more of the individual features mentioned or
evident from the text or drawings. All of these different
combinations constitute various alternative aspects of the
invention.
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